Segawa Syndrome – Causes, Symptoms & Treatment

Segawa Syndrome

Segawa Syndrome is a very rare inherited nervous system disease with symptoms similar to Parkinson’s disease . The disease belongs to the large group of dystonias, which are characterized by stiffening of the muscles. With proper diagnosis of the disease, treatment is very simple and successful.

What is Segawa Syndrome?

The Segawa syndrome as an extremely rare hereditary disease of the nervous system belongs to the large heterogeneous group of dystonia . Dystonia is characterized by stiffening of the muscles caused by a disturbance in muscle tone. Involuntary contractions of the skeletal muscles take place.

Cramps and abnormal postures occur that are sustained for a long time. However, the individual dystonia have different causes. Segawa syndrome is an idiopathic dystonia, i.e. muscle stiffness without an externally recognizable cause.

It is now known that the disease is hereditary. The clinical picture of Segawa syndrome was first described by the Japanese neurologist Masaya Segawa in 1970. He also recognized that it is a disease in its own right.

Since the syndrome has many similarities with Parkinson ‘s disease , it is still often confused with this disease and sometimes it is referred to as atypical Parkinson’s disease. However, Segawa syndrome has nothing to do with Parkinson’s disease. In both diseases there are disturbances in the dopamine metabolism.

However, their causes are completely different. The disease manifests itself differently in the individual patient and is therefore often not diagnosed immediately. Therefore, their frequency is not exactly known. It is estimated that one in every million people suffers from Segawa Syndrome.


gene mutation on the long arm of chromosome 14 is thought to be the cause of Segawa syndrome. It is the GCH1 gene, which encodes the enzyme GTP cyclohydrolase. GTP cyclohydrolase is the rate-limiting enzyme in the synthesis of tetrahydrobiopterin (BH4).

Tetrahydrobiopterin, in turn, is responsible for the formation of dopamine. A mutation of the GCH1 gene can therefore lead to a lack of BH4 and thus of dopamine. The mutation is inherited in an autosomal dominant manner. However, the penetrance of the gene defect varies. In some patients, there are hardly any symptoms, while in others they are severe.

In some cases, an autosomal recessive inheritance is also suspected, but this is said to go back to another gene. This gene is located on chromosome 11 and is responsible for encoding tyrosine hydroxylase. As a result of the gene defects described, there is a lack of dopamine. Because of the delayed synthesis, the neurotransmitter cannot be synthesized again quickly enough after it has been consumed.

Stores for dopamine are depleted and, after a period of physical activity, are no longer available for muscle reactions. Muscle tightening occurs.

Symptoms, Ailments & Signs

The Segawa syndrome first manifests itself as a gait disorder , which worsens over the course of the day. The feet are placed in an inward position. This position can become so rigid that further movement becomes impossible.

It can happen that affected children go to school alone early in the morning and may even have to be picked up in a wheelchair in the afternoon because they can no longer walk. In the course of physical activity, dopamine stores are used up in this disease and are not replenished quickly enough.

In addition to the inward rotation of the feet, Parkinson-like symptoms such as general muscle stiffness, lack of movement , tremors or the loss of postural reflexes can also occur. It was also found that more female than male patients are affected by Segawa syndrome. The first symptoms usually appear in the first decade of life, between the ages of four and eight. In a few cases, however, the symptoms do not begin until early adulthood.

Diagnosis & disease progression

Segawa syndrome is actually very easy to diagnose. The diagnosis can already be made on the basis of the typical symptoms. It is typical of this disease that the inability to move always sets in during the day after physical activity. After periods of rest or after a night’s sleep, the symptoms gradually disappear.

The reason for this is to be found in the slow production of dopamine in the body. After the correct diagnosis, Segawa syndrome is also the only dystonia that can be treated causally until symptoms are free. However, because this disease is so rare, it often goes undetected by the examining physicians. Misdiagnosis occurs, which often initiates another path of suffering for some patients.


Segawa syndrome can cause serious complications. The typical gait disorders occasionally lead to accidents and falls, which in turn lead to fractures and injuries. In general, the condition causes severe physical discomfort. Symptoms such as tremors and muscle stiffness represent a significant psychological burden for those affected in the long term.

The consequences are mental illnesses such as depression, anxiety disorders or inferiority complexes. Since it is mostly children who are affected, parents often suffer as well. The need for care for one’s own children is associated with stress and anxiety, which can also develop into serious mental illnesses in the long term. Therapy for Segawa syndrome can also cause adverse events.

The typically prescribed preparation L-DOPA can cause serious side effects. Typical symptoms include disturbances in movement, nausea and vomiting, urine discoloration and abdominal pain. Psychological disorders such as restlessness, anxiety disorders and mood disorders are also common.

Insomnia is just as possible as indigestion, muscle stiffness, increased sweating and uncontrolled movements. In individual cases, side effects such as stomach bleeding, skin rashes and liver inflammation with bile stasis occur. Allergic reactions to the administered preparations cannot be ruled out either.

When should you go to the doctor?

Segawa syndrome must always be evaluated and treated by a doctor. Self-healing cannot occur in this case, since this disease is a hereditary disease, which can therefore not be treated causally, but only purely symptomatically. Early diagnosis and treatment of the syndrome have a positive effect on the further course.

A doctor should be consulted for Segawa syndrome if the person affected suffers from a severe gait disorder, with this gait disorder usually becoming significantly worse if left untreated. Those affected are then often dependent on a walking aid or even a wheelchair and can no longer cope with their everyday life on their own. Muscle tremors also indicate Segawa syndrome.

If these symptoms occur, a doctor must be consulted in any case. The diagnosis of Segawa syndrome is made by a general practitioner or by an orthopedist , although further treatment must be carried out by a specialist. A full cure cannot be obtained.

Treatment & Therapy

After the correct diagnosis, Segawa syndrome can be treated very well. Although the disease cannot be cured due to its hereditary nature, no symptoms appear with lifelong drug treatment. Only the lack of production of dopamine has to be compensated by substitution of L-DOPA (levodopa).

L-DOPA is a prodrug that is converted into dopamine in the brain. Dopamine itself cannot be administered because it cannot cross the blood-brain barrier. However, L-DOPA can do this. By splitting off carbon dioxide, it then forms dopamine in the brain, which maintains the mobility of the muscles.


Prevention of Segawa syndrome is not possible. It is hereditary and no family history has been observed. After the typical symptoms first appear, only lifelong substitution with levodopa can ensure freedom from symptoms.


Those affected with Segawa syndrome usually only have a few and only very limited measures of direct aftercare available. For this reason, the affected person should ideally consult a doctor at an early stage in order to prevent the occurrence of other complications and symptoms. Segawa syndrome cannot heal on its own.

Since Segawa syndrome is a hereditary disease, it cannot usually be completely cured. For this reason, the affected person should have a genetic examination and counseling carried out if they wish to have children in order to prevent the disease from recurring in their descendants. Some of the symptoms can be alleviated by taking various medications.

The person concerned should ensure that the dosage is correct and that the medication is taken regularly in order to counteract the symptoms. Likewise, a doctor should be consulted first in the event of severe side effects or if anything is unclear. The further course of this syndrome is strongly dependent on the exact severity of the disease, so that no general prediction can be made. Eventually, Segawa syndrome limits the life expectancy of the patient.

You can do that yourself

Segawa syndrome leads to impaired gait in everyday life and sometimes to falls. It is therefore very important for those affected to take the prescribed medication correctly. The symptoms can only be avoided successfully and in the long term with the appropriate medication.

The typical movement problems typically appear after physical activity and decrease after a rest or a good night’s sleep. Therefore, there is a risk that those affected will recognize the problem too late. A medical diagnosis helps to analyze and treat the rare disease. In contrast to other dystonia, it can be treated successfully so that those affected no longer have any symptoms. To minimize complications, patients should exercise caution when they experience the first signs of gait disturbance. In this way, accidents and injuries can be avoided in good time.

The drugs help against the physical discomfort. Especially when the typical tremor occurs in combination with a stiffening of the muscles, the psyche also suffers from the disease. This can lead to feelings of anxiety, complexes and depression. If children are affected, parents should obtain comprehensive information in order to be able to help their offspring. This reduces the stress level and psychological complications do not occur so quickly.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.